Nuclear
Power

TVA runs three nuclear power plants. Nuclear power makes about 38 percent of all the electricity generated by TVA, and about 20 percent of all the electricity generated in the United States.

Nuclear
power is produced when the atoms that make up enriched uranium
are split. Uranium is mined from the ground, just like coal or copper
or silver ore. The uranium is then formed into pellets that are
put in tubes inside a nuclear reactor.

The pellets
are bombarded with neutrons, which cause the uranium atoms to split.
This is called nuclear fission. Nuclear fission creates enormous
amounts of heat, which is used to turn water into steam. The steam
is used to turn turbine blades, the blades spin the plants
generator, and the generator makes electricity.

Although many
people dont know it, there are actually two different types
of nuclear power plants. They both make electricity, but in different
ways.

Boiling-water
reactors turn water into steam in the reactor core, and the
steam turns the plants turbine and generator. TVA’s Browns
Ferry Nuclear Plant is a boiling-water reactor.

Pressurized-water
reactors, such as TVA’s Sequoyah and Watts Bar nuclear plants,
dont turn water to steam in the reactor core. The water passing
through the core is very hot, but it is kept under pressure as a
liquid. It flows to a separate area of the plant called a steam
generator, where it turns a second supply of water into steam.

The pressurized
water goes back to the reactor core to be heated again, and the
steam from the second source of water is used to run the generator
to make electricity.

Pressurized-water
plants like Sequoyah and Watts Bar are much more common in the United
States. About 70 percent of U.S. nuclear power plants are pressurized-water
reactors.

What
is uranium?

Uranium is the heaviest of all the naturally occurring elements (hydrogen is the
lightest). It is a radioactive element, which means it naturally gives
off radiation.

Uranium
is surprisingly common and can be found in most rocks in tiny concentrations.
Much of the earths internal heat is thought to be the result of
nuclear reactions of uranium and thorium, another radioactive element.